Featuring a typical, linear fifteen-mission campaign and skirmish matches (both against the AI and online) limited to two or four players on only eight maps, the highlight of Grey Goo is distinctive three factions: the expansionist Beta, defensive Humans, and mobile Goo. The interface is usually fantastic, offering quick access to economic status, build orders, and automated production. A single resource is collected at fixed locations on the map, used to place factories and other buildings, construct units (a typical assortment of infantry, tank, artillery, and flying options), and research tech upgrades. Maps also contain brush where units can hide. The AI is not smart unless they are given an economic boost on “high” difficulty, and friendly units have trouble attacking while moving and prioritizing enemy units over static defensive structures. Grey Good has some innovative features but a handful of limitations as well.